2 * CAM request queue management definitions.
4 * Copyright (c) 1997 Justin T. Gibbs.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions, and the following disclaimer,
12 * without modification, immediately at the beginning of the file.
13 * 2. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
20 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #ifndef _CAM_CAM_QUEUE_H
32 #define _CAM_CAM_QUEUE_H 1
36 #include <sys/queue.h>
40 * This structure implements a heap based priority queue. The queue
41 * assumes that the objects stored in it begin with a cam_qentry
42 * structure holding the priority information used to sort the objects.
43 * This structure is opaque to clients (outside of the XPT layer) to allow
44 * the implementation to change without affecting them.
47 cam_pinfo **queue_array;
51 u_int32_t qfrozen_cnt;
54 TAILQ_HEAD(ccb_hdr_tailq, ccb_hdr);
55 LIST_HEAD(ccb_hdr_list, ccb_hdr);
56 SLIST_HEAD(ccb_hdr_slist, ccb_hdr);
60 struct ccb_hdr_tailq queue_extra_head;
61 int queue_extra_entries;
72 struct camq send_queue;
78 struct cam_devq *cam_devq_alloc(int devices, int openings);
80 int cam_devq_init(struct cam_devq *devq, int devices,
83 void cam_devq_free(struct cam_devq *devq);
85 u_int32_t cam_devq_resize(struct cam_devq *camq, int openings);
88 * Allocate a cam_ccb_queue structure and initialize it.
90 struct cam_ccbq *cam_ccbq_alloc(int openings);
92 u_int32_t cam_ccbq_resize(struct cam_ccbq *ccbq, int devices);
94 int cam_ccbq_init(struct cam_ccbq *ccbq, int openings);
96 void cam_ccbq_free(struct cam_ccbq *ccbq);
98 void cam_ccbq_fini(struct cam_ccbq *ccbq);
101 * Allocate and initialize a cam_queue structure.
103 struct camq *camq_alloc(int size);
108 u_int32_t camq_resize(struct camq *queue, int new_size);
111 * Initialize a camq structure. Return 0 on success, 1 on failure.
113 int camq_init(struct camq *camq, int size);
116 * Free a cam_queue structure. This should only be called if a controller
117 * driver failes somehow during its attach routine or is unloaded and has
118 * obtained a cam_queue structure.
120 void camq_free(struct camq *queue);
123 * Finialize any internal storage or state of a cam_queue.
125 void camq_fini(struct camq *queue);
128 * cam_queue_insert: Given a CAM queue with at least one open spot,
129 * insert the new entry maintaining order.
131 void camq_insert(struct camq *queue, cam_pinfo *new_entry);
134 * camq_remove: Remove and arbitrary entry from the queue maintaining
137 cam_pinfo *camq_remove(struct camq *queue, int index);
138 #define CAMQ_HEAD 1 /* Head of queue index */
140 /* Index the first element in the heap */
141 #define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
143 /* Get the first element priority. */
144 #define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ? \
145 ((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
148 * camq_change_priority: Raise or lower the priority of an entry
149 * maintaining queue order.
151 void camq_change_priority(struct camq *queue, int index,
152 u_int32_t new_priority);
155 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq);
158 cam_ccbq_take_opening(struct cam_ccbq *ccbq);
161 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb);
164 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb);
166 static __inline union ccb *
167 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index);
170 cam_ccbq_send_ccb(struct cam_ccbq *queue, union ccb *send_ccb);
173 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb);
176 cam_ccbq_release_opening(struct cam_ccbq *ccbq);
180 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
182 return (ccbq->queue.entries + ccbq->queue_extra_entries);
186 cam_ccbq_take_opening(struct cam_ccbq *ccbq)
188 ccbq->devq_openings--;
193 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
195 struct ccb_hdr *old_ccb;
196 struct camq *queue = &ccbq->queue;
201 * If queue is already full, try to resize.
202 * If resize fail, push CCB with lowest priority out to the TAILQ.
204 if (queue->entries == queue->array_size &&
205 camq_resize(&ccbq->queue, queue->array_size * 2) != CAM_REQ_CMP) {
206 old_ccb = (struct ccb_hdr *)camq_remove(queue, queue->entries);
207 TAILQ_INSERT_HEAD(&ccbq->queue_extra_head, old_ccb,
209 old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
210 ccbq->queue_extra_entries++;
213 camq_insert(queue, &new_ccb->ccb_h.pinfo);
217 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
219 struct ccb_hdr *cccb, *bccb;
220 struct camq *queue = &ccbq->queue;
222 /* If the CCB is on the TAILQ, remove it from there. */
223 if (ccb->ccb_h.pinfo.index == CAM_EXTRAQ_INDEX) {
224 TAILQ_REMOVE(&ccbq->queue_extra_head, &ccb->ccb_h,
226 ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
227 ccbq->queue_extra_entries--;
231 camq_remove(queue, ccb->ccb_h.pinfo.index);
234 * If there are some CCBs on TAILQ, find the best one and move it
235 * to the emptied space in the queue.
237 bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
240 TAILQ_FOREACH(cccb, &ccbq->queue_extra_head, xpt_links.tqe) {
241 if (bccb->pinfo.priority > cccb->pinfo.priority ||
242 (bccb->pinfo.priority == cccb->pinfo.priority &&
243 GENERATIONCMP(bccb->pinfo.generation, >,
244 cccb->pinfo.generation)))
247 TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
248 ccbq->queue_extra_entries--;
249 camq_insert(queue, &bccb->pinfo);
252 static __inline union ccb *
253 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
255 return((union ccb *)ccbq->queue.queue_array[index]);
259 cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
262 send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
264 ccbq->dev_openings--;
268 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
272 ccbq->dev_openings++;
277 cam_ccbq_release_opening(struct cam_ccbq *ccbq)
280 ccbq->devq_openings++;
284 #endif /* _CAM_CAM_QUEUE_H */